Apparatus for heating an elongated metal workpiece



M h 1968 c. P. PORTERFIELD 3,372,261

APPARATUS FOR HEATING AN ELONGATED METAL WORKFIECE Filed June 17, 1965 v INVENTOR. U u CECIL P. PORTERFIELD ATTORNEYS United States Patent Chice 3,372,261 APPARATUS FOR HEATING AN ELUNGATED METAL WQRKPIECE Cecil P. Porteriielcl, Cleveland, Ohio, assignor to The Ohio Crankshaft Company, Cleveland, Uhio, a corporation of Qino Filed June 17, 1965, Ser. No. 464,753 6 Claims. (0. 2l9-'10.1)

ABSTRACT OF THE DliSCLOSURE There is provided an apparatus for heating a wire as it moves along a longitudinal path. This apparatus includes two generally telescoped, rotatable drums with a plurality of mutually facing permanent magnets. The drums are rotated to bring together opposite polarity magnets on opposite sides of the path of the moving wire. These opposite polarity magnets are moved across the path to create heating currents in the wire, without actually coming in contact with the wire.

Disclosure This invention pertains to the art of heating a metal workpiece and more particularly to an apparatus for heating an elongated metal workpiece.

, The present invention is particularly applicable for heating a longitudinally moving metal wire, and it will be described with particular reference thereto; however, it will be appreciated that the invention has much broader applications and may be used for heating various elongated metal workpieces, such as, without limitation, metal tubes, billets, bars, etc.

, During the production of small gage metal wire, it is often necessary to heat the wire for various purposes. For instance, if the wire is being drawn into successively smaller sizes, each drawing operation results in a certain amount of cold working. Generally the cold worked wire cannot be processed efficiently through the remainder of the drawing line; therefore, it is somewhat common practice toanneal the wire by applying heat to the wire during the drawing or processing thereof. Annealing of the wire removes the work hardness and makes the wire susceptible to further drawing or processing.

Since the annealing operation often must be accomplished in an intermediate stage of the manufacturing process, it is inconvenient, and impractical, to coil the wire onto a spool so that the wire may be placed within a soaking furnace. Annealing in this manner completely disrupts the continuous aspect of the process line. To overcome this difliculty, it has been proposed to pass the moving wire through a mufiie type furnace which raises the temperature of the Wire to the annealing temperature by conduction of heat through air, or another medium. Since the wire is moving rapidly, such a furnace generally requires a considerable length. This makes it impractical.

To overcome the difficulties encountered in heating a moving wire in a muflle furnace, many devices have been proposed to introduce electrical currents into the wire itself so that the wire is heated by the PR heating effect of currents circulating within the wire. These devices generally take the form of spaced contacts sliding on the surface of the wire or an induction coil surrounding the wire. Although such devices have proved somewhat successful, there are certain disadvantages. For instance, the sliding contacts often cause arcing between the contacts and the wire. This mars the surface of the wire and, in many instances, distracts from the usefulness of the finished product..The induction coil devices generally require a sizable loop of wire entrained around spaced guide members.

3,3722% Patented Mar. 5, 1968 This often results in an expensive and, somewhat, cumbersome device for accomplishing the desired heating of the wire.

These and other disadvantages of prior methods and apparatus for heating a longitudinally moving wire are completely overcome by the present invention which is directed toward an apparatus for heating an elongated metal workpiece, such as a wire, which apparatus does not require sliding contacts or a complicated guiding arrangement to form a loop of wire to be used with an induction coil.

In accordance with the broadest aspect of the present invention, there is provided an apparatus for heating an elongated metal workpiece as it moves longitudinally along a give path. This apparatus comprises a number of separate pairs of north and south permanent magnet poles spaced longitudinally along the path with the poles of each pair being on opposite sides of the path and means for moving the pairs of poles in a direction transverse of the path and through the path. In this manner, the field between the poles in each pair intersects the workpiece and all of these fields create longitudinally spaced heating areas in the elongated, moving workpiece.

In accordance with a more limited aspect of the present invention, there is provided an apparatus for heating an elongated metal workpiece as it moves lonigudinally along a given path. The apparatus comprises an outer drum rotated about an axis generally parallel with the workpiece path, an inner drum, smaller than the outer drum, and rotated within the outer drum on the axis generally parallel with the workpiece path, and means for synchronizing the rate of rotation of these two drums. The workpiece path extends between these two drums so that a plurality of permanent magnets secured onto the inner surface of the outer drum and the outer surface of the inner drum can coact to introduce heating currents within the workpiece as it is moving through the drums. The magnets face radially from the drums toward each other and the pole faces on the ends of these magnets are arranged in a series of longitudinally spaced annular patterns with each pattern having alternate north and south magnetic pole faces and with the annular pattern on one drum being longitudinally aligned with an annular pattern on the other drum.

By constructing an apparatus in accordance with this aspect of the present invention, the synchronized drums cause permanent magnets having opposite polarity to coact as they are moving past the wire. These coacting magnetic poles create a magnetic flux field which passes transversely through the wire and establishes a voltage potential within the wire. The voltage potential, in turn, creates circulating currents that heat the moving wire. By providing a plurality of longitudinally spaced sets of magnets the hating takes place at spaced areas along the length of the wire. In this mnner, the temperture of the wire can be easily increased to the annealing temperature or to any other predetermined temperature without requiring phys ical contact with the moving wire.

The permanent magnets also serve as a means for centering the wire as it moves between the two drums. The currents created within the wire establish opposing flux fields which coact with the flux field between the magnets to create a centering force in the wire.

The primary object of the present invention is the provision of an apparatus for heating an elongated, moving, metal workpiece which apparatus does not physically contact the workpiece or require complicated guide structures for supporting the workpiece.

Another object of the present invention is the provision of an apparatus for heating an elongated, moving, metal workpiece which apparatus includes longitudinally spaced pairs of opposite polarity, permanent magnet poles and means for moving the pairs of poles transversely past the workpiece to create longitudinally spaced heating areas within the workpiece.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the invention as read in connection with the 'accompanying drawing in which:

FIGURE 1 is a pictorial view illustrating, somewhat schematically, the preferred embodiment of the present invention;

FIGURE 2 is an enlarged cross-sectional view taken generally along line 2-2 of FIGURE 1;

FIGURE 3 is a schematic, cross-sectional view taken generally along line 3-3 of FIGURE 1; and

FIGURE 4 is "a view similar to FIGURE 3 showing a modification of the preferred embodiment of the present invention.

Referring now to the drawing wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting same, FIGURES l-3 show an apparatus A for heating an elongated workpiece, such as a wire B, moving in a longitudinal direction along. a path defined by axis b. It is appreciated that various other elongated workpieces could be heated by apparatus A, without departing from the intended spirit and scope of the present invention. Basically, the apparatus A includes an outer drum I'll, rotatable on an axis x, an-inner drum 12, somewhat smaller in diameter than drum 10 and rotatable on an axis y, and a base 14 for supporting the two drums. As shown in FIGURE 2, the axes x, y and b are generally in the same horizontal plane, and the wire B passes between the drums 10, 12 at a location where the drums are the closest.

Referring in more detail to drum It the drum includes longitudinally spaced support flanges Ztl, 22 which are received within rollers 24 rotatably secured onto spaced plates 26, 28. In this manner, the drum 1% can be rotated about the axis x. Drum 10 is rotated by a gear drive flange 30 adjacent support flange 22 and a drive gear 32 driven by a motor 34 supported on plates 36 by supports 38. The motor may take a variety of forms; however, the speed of the motor must be controlled within relatively close limits. In accordance with the illustrated embodiment of the invention, the motor 34 is energized by leads 4%, 42.

Drum 1% also includes a radially inwardly facing cylindrical surface 50 having provided thereon a plurality of permanent magnets 52. These magnets are positioned in longitudinally spaced annular patterns 54. One of these patterns is shown in more detail in FIGURE 2. An even number of permanent magnets are provided in each pattern 54, and the polarity of the magnets in each pattern is alternated between north and south. Thus, each magnet has adjacent thereto permanent magnets of opposite polarity.

Referring now to the inner drum 12, the drum includes longitudinally spaced support flanges 6t 62 received by support rollers 64 which are rotatably secured on spaced support plates 66, 68. The plates 66, 68 are movable within guides 70, 72 in a direction generally parallel to the plane defined by axes x, y and b. To accomplish the movement of drum 12, support plate 66 is provided wi h a rack portion 74 that coacts with a pinion 76 of motor 78 whereby rotation of the pinion shifts the inner drum 12 along the line represented by the horizontal arrows in FIGURE 2.

One end of the inner drum 12 is provided with a drive flange 80 meshed with a drive gear 82 driven by motor 84. The motor is supported on the movable plate 68 by a plate 86 and supports 88. Motor 84 is an adjustable speed motor having input leads 911, $2. This motor does not substantially differ from motor 34 utilized to rotate the outer drum 10.

Drum 12 is provided with a radially outwardly facing cylindrical surface onto which a plurality of permanent magnets 102, similar to permanent magnets 52, are secured in a plurality of longitudinally spaced annular patterns 1%. One of these patterns is shown in FIGURE 2. In FIGURE 3, it is seen that the annular patterns 104 of the magnets on drum 12 are longitudinally aligned with patterns 54 of the permanent magnets on the outer drum 1%. As in the case of the magnets forming the patterns 54, the magnets within each pattern 109 of the inner drum 12 are arranged to present alternate north and south magnetic poles. This is best shown in FIGURE 2.

In operation of apparatus A, reference is made to FIGURE 2. The wire B moves between drums 10, 12 and the drums are rotated in a direction indicated by the arcuate arrows adjacent the drums. The speed of the drums is coordinated so that a permanent magnet on the surface 50 will be directly across from an opposite polarity permanent magnet on surface 100 when these magnets move past wire B. To accomplish this, the surface speed of the magnets when in the vicinity of wire B must be substantially the same. Of course, the inherent attraction between opposite polarity magnetic poles will assist in maintaining the synchronization of two drums as they are rotated. The magnetic field 1% between the moving magnets intersects the wire and causes a current flow in the portion of the wire subjected to the magnetic field. This ere-ates internal heating of the wire without requiring physical contact with the wire or a complicated guiding system for the wire. As the drums are rotated further, the poles of the next pair of the permanent magnets are brought together and create a successive magnetic field which passes transversely through the wire B. This same action of successive fields intersecting the wire is taking place in a number of longitudinally spaced areas of the wire. Consequently, the total heating effect of the wire, or the summation of the heating in these spaced areas, is sufficient to accomplish the desired temperature within the wire.

A variety of structures could be utilized for synchronizing the two drums so that opposite polarity magnetic poles will register with each other as the poles pass the wire. For illustrative purposes only, the synchronizing mechanism is schematically shown in FIGURE 1 as a synchronizer 1 10 connected to motors 34, 84 by leads 112, 114 and leads 116, 118, respectively. A. dial or other adjusting mechanism 120 can be used to change the speed of the drums without changing the synchronization thereof. It is also possible to provide an arrangement for adjusting the speed of motors 34, 34 individually if the synchronization caused by. synchronizer is slightly off. Of course, it would be possible to provide a gear train between the separate drums for mechanically synchronizing the same.

The heating effect of apparatus A can be changed by a variety of adjustments. For instance, the speed of the wire B passing through the apparatus A may be changed or the length of the apparatus A may be changed. Since adjustment of the heating effect by these modifications is somewhat impractical, in, accordance with the illustrated embodiment of the invention, the heating effect is changed by adjusting the rotational speed of the drums. This is accomplished by changing indicator which changes the speed of both drums without affecting syn,- chronization of the drums. In addition, the motor 78 may be energized to shift the position of the inner drum with respect to the outer drum. This reduces the flux density between the magnetic poles and changes the heating effect of the magnetic fields. It is also appreciated that an arrangement could be provided for -moving the outer drum with respect to the inner drum.

Referring now to FIGURE 4, a modification of the present invention is illustrated. In this modification, the permanent magnets on the outer drum 10 are arranged in longitudinally spaced, alternate annular patterns 130, 132 with the magnets in pattern being offset in a circumferential direction from the magnets in pattern 132. In like manner, the longitudinally spaced, annular pattern of magnets on the inner drum 12 are also offset with the magnets in pattern 140 being offset circumferentially from the magnets in the pattern 142. Otherwise, the apparatus shown in FIGURE 4 operates substantially as the apparatus A shown in FIGURES 1-3. By circumferentially offsetting the magnets in adjacent magnet patterns, the current heating areas within the Wire B are created at different times. In other words, heating caused by the matching magnets in patterns 130, 140 occurs at a different time than heating caused by the matching magnets in patterns 132, 142. Consequently, the heating of the wire changes from one longitudinal area to another and, in effect, provides a heating area which progresses along the length of the Wire as the drums 10, 12 are rotated.

By providing two magnets which come together in the area of the wire B, a strong magnetic field is created as the magnets draw the field through the wire. This creates a positive and substantial heating of the wire B.

The present invention has been described in connection with two preferred embodiments; however, it should be appreciated that various modifications may be made in these embodiments without departing from the intended spirit and scope of the present invention as defined in the appended claims.

Having thus defined my invention, I claim:

1. An apparatus for heating an elongated metal workpiece as it moves longitudinally along a given path, said apparatus comprising: an outer drum-like first member having a radially inwardly facing, generally cylindrical surface; means for rotating said first member on a first axis generally parallel with said path; an inner drumlike second member having a radially outwardly facing, generally cylindrical surface smaller than said inwardly facing surface; means for rotating said second member Within said first member and on a second axis generally parallel with said path; said path, first axis and second axis being substantially in the same plane with said path being between said surfaces; a plurality of permanent magnets secured onto each of said surfaces; said magnets facing radially from said surfaces and having outer pole faces; said magnets being arranged on each member in a series of longitudinally spaced annular patterns with each pattern having alternate north and south magnetic pole faces and an annular pattern of one member being longitudinally aligned with an annular pattern of the other member; and means for synchronizing the rate of rotation of said members to allow a pole face on said first member to coincide with an opposite polarity pole face of said second member as said pole faces pass through said plane.

2. An apparatus as defined in claim 1 wherein said pole faces in adjacent patterns on each of said members are circumferentially shifted from each other a distance equal to approximately one half the spacing between adjacent pole faces in each pattern.

3. An apparatus as defined in claim 1 including means for changing the spacing between said axes to change the spacing of the pole faces as they pass through said plane.

4. An apparatus as defined in claim 1 wherein the annular patterns on said second member have less magnets than the patterns on said first member.

5. An apparatus for heating an elongated metal workpiece as it moves longitudinally along a given path, said apparatus comprising: an outer drum-like first member having a radially inwardly facing, generally cylindrical surface; a first motor means for rotating said first member on a first axis generally parallel with said path; an inner drum-like second member having a radially outwardly facing, generally cylindrical surface smaller than said inwardly facing surface; a second motor means for rotating said second member within said first member and on a second axis generally parallel with said path; said path, first axis and second axis being substantially in the same plane with said path being between said surfaces; a plurality of permanent magnets secured onto each of said surfaces; said magnets facing radially from said surfaces and having outer pole faces; said magnets being arranged on each member in a series of longitudinally spaced annular patterns with each pattern having alternate north and south magnetic pole faces and an annular pattern of one member being longitudinally aligned with an annular pattern of the other member; and means for synchronizing said first and second motor means to allow a pole face on said first member to coin cide with an opposite polarity pole face of said second member as said pole faces pass through said plane.

6. An apparatus for heating an elongated metal workpiece as it moves longitudinally along a given feedline, said apparatus comprising: a plurality of first permanent magnets, means for moving said first magnets in first given paths, a plurality of second permanent magnets having polarities opposite to said first permanent magnets, means -for moving said second magnets in second given paths, said first and second given paths coming together, but slightly spaced, at said feedline, said paths being in a plane transverse to said feedline and spaced substantially from each other remote from said feedline.

References Cited UNITED STATES PATENTS 9/1959 Lockner et al. 21910.61 X 9/1966 Baermann 219-1061 

